Cornerback Will Redmond, a third-round draft pick out of Mississippi State who was selected despite tearing his right ACL as a junior, was placed on injured reserve Monday. The designation means Redmond will miss a minimum of six games this season. He can begin practicing after six weeks, then must be activated within a two-week window or be placed on injured reserve for the rest of the season.

Redmond injured the knee October of 2015, but Baalke said when Redmond was drafted the 49ers were comfortable he would be ready for training camp. Redmond was not ready when camp opened but he played well in his two exhibiton games. He had four tackles and a sack against Green Bay and five tackles in the finale against San Diego, including one on special teams.

Only Carradine and Reaser will be on the 53-man roster when the 49ers open the season Sept. 12 against the Los Angeles Rams.

To replace Redmond on the roster, the 49ers signed running back DuJuan Harris.

Harris, who had been waived Saturday, joins Carlos Hyde, Shaun Draughn and Mike Davis as the fourth running back on the 49ers roster. He was the second- leading rusher behind Davis for the 49ers in the exhibtion season, gaining 131 yards on 28 carries. He had one touchdown and lost a fumble.

Last season, Harris gained 140 yards on 27 carries with no touchdowns for the 49ers in two games. He was signed off the Baltimore Ravens practice squad after being released by Seattle.

--- Taylor Hart, a defensive tackle who played for coach Chip Kelly at both Oregon and with the Philadelphia Eagles, was claimed off wiavers. Hart (6-foot-6, 305 pounds), played in 14 games last season with 30 tackles, starting once. To make room on the roster, safety L.J. McCray was waived.